John Isner pumps his fist after winning a point against Philipp Kohlschreiber, of Germany, in the third round of play at the 2012 US Open tennis tournament, early Monday, Sept. 3, 2012 in New York. The match began on Sunday evening. (AP Photo/Charles Krupa)

John Isner wraps his head with ice wrapped in a towel during his match with Philipp Kohlschreiber, of Germany, in the third round of play at the 2012 US Open tennis tournament, early Monday, Sept. 3, 2012 in New York. The match began on Sunday evening. (AP Photo/Charles Krupa)

Maria Sharapova, of Russia, raises her fist after beating Nadia Petrova, of Russia, 6-1, 4-6, 6-4 in the fourth round of play at the 2012 US Open tennis tournament, Sunday, Sept. 2, 2012 in New York. (AP Photo/Charles Krupa)

Nadia Petrova, of Russia, catches her racquet after throwing it in the air during her fourth-round match against Maria Sharapova, of Russia, at the U.S. Open tennis tournament, Sunday, Sept. 2, 2012, in New York. Sharapova won 6-1, 4-6, 6-4. (AP Photo/Henny Ray Abrams)

Marion Bartoli, of France, reacts during a match against Petra Kvitova, of the Czech Republic, in the fourth round of play at the 2012 US Open tennis tournament, Sunday, Sept. 2, 2012, in New York. (AP Photo/Charles Krupa)

Samantha Stosur, of Australia, signs autographs after winning her match against Britain's Laura Robson in the fourth round of play at the 2012 US Open tennis tournament, Sunday, Sept. 2, 2012, in New York. (AP Photo/Kathy Willens)

Samantha Stosur, of Australia, serves to Britain's Laura Robson in the third round of play at the 2012 US Open tennis tournament, Sunday, Sept. 2, 2012, in New York. Stosur won the match. (AP Photo/Mel C. Evans)

Richard Gasquet, of France, waves as he leaves the court after his match against Steve Johnson in the fourth round of play at the 2012 US Open tennis tournament, Sunday, Sept. 2, 2012, in New York. Gasquet won the match. (AP Photo/Paul Bereswill)

Samantha Stosur, of Australia, reacts after winning her match Britain's Laura Robson in the fourth round of play at the 2012 US Open tennis tournament, Sunday, Sept. 2, 2012, in New York. (AP Photo/Kathy Willens)

Marion Bartoli, of France, returns a shot to Petra Kvitova, of the Czech Republic, in the fourth round of play at the U.S. Open tennis tournament, Sunday, Sept. 2, 2012, in New York. Bartoli won 1-6, 6-2, 6-0. (AP Photo/Henny Ray Abrams)

Steve Johnson stops himself at the wall for the court during his match against Richard Gasquet, of France, in the third round of play at the 2012 US Open tennis tournament, Sunday, Sept. 2, 2012, in New York. (AP Photo/Paul Bereswill)

Janko Tipsarevic, of Serbia, returns a drop shot at the net against Grega Zemlja, of Slovenia, in the third round of play at the U.S. Open tennis tournament, Sunday, Sept. 2, 2012, in New York. Tipsarevic won 6-4, 6-3, 7-5. (AP Photo/Charles Krupa)

Maria Sharapova, of Russia, raises her fist after defeating Nadia Petrova, of Russia, 6-1, 4-6, 6-4 in the fourth round of play at the U.S. Open tennis tournament, Sunday, Sept. 2, 2012, in New York. (AP Photo/Charles Krupa)

Argentina's Juan Martin Del Potro reacts during his match against Argentina's Leonardo Mayer in the third round of play at the 2012 US Open tennis tournament, Sunday, Sept. 2, 2012, in New York. (AP Photo/Paul Bereswill)

NEW YORK — Knowing full well each match could be his last, Andy Roddick is putting on a show while soaking up every moment along the way.

So when he pounded a forehand passing shot to seize a 20-stroke point Sunday, Roddick thrust both arms overhead, motioning to the full house of U.S. Open spectators to make even more noise. Moments later, after hitting a winning volley, Roddick wagged his right index finger while chugging back to the baseline.

Channeling his inner Jimmy Connors, Roddick is having a grand ol’ time at his retirement party — and he’s not done yet.

Winning a second consecutive match since announcing the U.S. Open will be the last tournament of his career, 2003 champion Roddick stuck around at least a little longer by getting past 59th-ranked Fabio Fognini of Italy 7-5, 7-6 (1), 4-6, 6-4 in the third round Sunday.

“I’d be an idiot not to use the crowd right now. It’s a huge advantage,” Roddick said. “Each match is almost like it’s another memory.”

What comes next could really be memorable. In the fourth round Tuesday, the last American man to win a Grand Slam title will face 2009 U.S. Open champion Juan Martin del Potro, who defeated Leonardo Mayer 6-3, 7-5, 7-6 (9) in an all-Argentine match that featured one particularly noteworthy point. In the tiebreaker, Mayer smacked a backhand that somehow ricocheted off the top of a net post and landed in the court — but del Potro was unfazed, got the ball back and wound up winning the point.

“I’m going to have to serve well, kind of try to rush him a little bit,” Roddick said about del Potro. “When he gets into a groove and has time, he’ll put a hurt on the ball.”

“I know this is special, this day, for him, but I’m doing my job,” said the seventh-seeded del Potro, whose major trophy is the only of the past 30 that wasn’t won by Roger Federer, Rafael Nadal or Novak Djokovic.

In women’s action, top-seeded Victoria Azarenka beat 73rd-ranked Anna Tatishvili 6-2, 6-2 to reach the quarterfinals at Flushing Meadows for the first time. Azarenka has dropped only 10 games through four matches heading into a showdown against defending champion Sam Stosur, a 6-4, 6-4 winner over 18-year-old Laura Robson of Britain, whose breakthrough run included wins against past major champions Kim Clijsters and Li Na.

Robson beat four-time major champion Kim Clijsters in the second round Wednesday, sending the 29-year-old Belgian into retirement. It was the next day, Roddick’s 30th birthday, that he surprisingly let the world know he had decided to walk away from the sport whenever this visit to Flushing Meadows ends.

Sunday just so happened to be five-time U.S. Open champion Connors’ 60th birthday — and on the very same date in 1991, Connors celebrated his 39th by coming back to beat Aaron Krickstein in five sets to reach the quarterfinals in New York, a match replayed often during rain delays in more recent times. Connors, who later briefly coached Roddick, was at his rabble-rousing, crowd-goading best on that day 21 years ago; in one of those nice twists, Roddick was in New York then, a kid who was treated to tickets as a present to celebrate his ninth birthday.

“That was my first taste of live tennis, and it was that run,” Roddick recalled, “so that’s as good as it gets.”

He and Fognini provided their own brand of entertainment, even though Roddick is not at his best because of an aching right shoulder. A couple of months ago, Roddick lowered the tension in his racket strings so he could, he explained while pointing to that shoulder, “get a little sling action in it and help the old Hamburger Helper here.”

Asked how that key part of his body feels, Roddick said: “It’s not great. But, you know, it’s good enough. I’ve got, max, a week of tennis left, so it’s good enough for that.”

An element of Roddick’s appeal, in addition to an ability to play tennis well enough to reach five Grand Slam finals and get to No. 1 in the ATP rankings, is his showmanship and quickness with a quip.

Dealing with a series of injuries, Roddick dropped out of the top 20 in February, then slid to No. 34 in March, his lowest ranking since 2001. A balky right hamstring forced Roddick to retire during his second-round match at the Australian Open in January, and he lost in the first round at the French Open and third round at Wimbledon.

The 20th-seeded Roddick certainly won’t be favored against del Potro. But Roddick is into the fourth round for the ninth time in 13 appearances in the U.S. Open, and he’s 8-0 so far.

“He benefits from playing at home,” said Fognini, who hugged his good pal up at the net after losing and asked for one of Roddick’s shirts as a memento.

“If I really force myself to pick a winner, I’d give del Potro a 51 percent chance, because he is playing well and he’s confident,” Fognini said. “But on the other hand, Roddick wants to end his career on a high note.”

Fognini is a real character, too, and he conjured up one tremendous, full-sprint, back-to-the-net, between-the-legs shot; after Roddick replied with a lunging volley winner into the open court to end the point, Fognini chucked his racket all the way to the service box.

“That’s about as cleanly as you can hit a between-the-legs passing shot. He hit the thing from Jersey and almost won the point,” Roddick said. “That was fun.”

There was more, including when Fognini stuck his mug right up against a TV camera after one point; requested instant-replay challenges of two faults on another (both serves were, indeed, out); and kept up a stream of sailor-language muttering in Italian.

Roddick appeared sluggish at times, and his big serve — he once owned the record for fastest, at 155 mph — wasn’t always what it can be. Fognini, who at 5-foot-10 is four inches shorter than Roddick, actually wound up with more aces, 15 to 10.

“I was surprised; he’s one of the best servers in the world,” Fognini said.

The key came in the second-set tiebreaker, when Fognini took the first point, and Roddick the rest.

At 1-all, Roddick really came alive, as did the partisan group in the stands, when he smacked a winner and gestured vigorously.

“I played that point perfectly. It was so pretty, it should have been framed,” Fognini said with a smile, “and he ruined it with a down-the-line passing shot that was crazy.”

Roddick followed that with a pair of aces at 126 mph and 131 mph and pretty much was on his way.

There was the third-set blip, of course, but otherwise Roddick stayed steady, breaking Fognini twice in a row in the fourth and raising his clenched right fist overhead after going up 4-3.

After Fognini missed a backhand return on match point, Roddick rolled his head back and raised both arms overhead, then swatted a ball into the stands.

Roddick answered the fans’ standing ovation with one of his own, clapping overhead while standing near the middle of the court. When he sat in his changeover chair, Roddick exhaled a couple of times, taking it all in.

“You’re kind of smiling, humming, whistling, walking around, and you feel pretty good about it. All of a sudden, you have to say good bye to someone. It’s like this gut-check moment. It’s these extreme emotions from five minutes to the next five minutes,” Roddick said, describing the past few days. “You think you know what’s going on, but I don’t think there’s any way to prepare yourself for it.”